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A cuttlefish with W-shaped pupils which may help them discern colors. All octopuses [25] and most cephalopods [26] [27] are considered to be color blind. Coleoid cephalopods (octopus, squid, cuttlefish) have a single photoreceptor type and lack the ability to determine color by comparing detected photon intensity across multiple spectral channels.
A veined octopus eating a crab. Unlike most other molluscs, all cephalopods are active predators (with the possible exceptions of the bigfin squid and vampire squid). Their need to locate and capture their prey has likely been the driving evolutionary force behind the development of their intelligence. [14]
Cuttlefish ink was formerly an important dye, called sepia. To extract the sepia pigment from a cuttlefish (or squid), the ink sac is removed and dried then dissolved in a dilute alkali. The resulting solution is filtered to isolate the pigment, which is then precipitated with dilute hydrochloric acid. The isolated precipitate is the sepia pigment.
Cephalopoda such as squid, cuttlefish, and octopuses are among the most neurologically advanced of all invertebrates. [26] The giant squid, which until recently had not been observed alive in its adult form, [27] is one of the largest invertebrates, surpassed in weight but not in length by the colossal squid. [28]
[10] Octopus eyes, too, look and work much like those of vertebrates; but there, Baer remarks, the similarities end. Cephalopods are "immensely foreign", with "a distributed sense of self" and a "lived reality" quite unlike human consciousness, a feature that, he notes, Godfrey-Smith calls "the most difficult aspect of octopus experience to ...
They have a seemingly simple brain, not the large complex brains of octopus, cuttlefish and squid, and had long been assumed to lack intelligence. But the cephalopod nervous system is quite different from that of other animals, and recent experiments have shown not only memory, but a changing response to the same event over time.
Bobtail squid (order Sepiolida) [1] are a group of cephalopods closely related to cuttlefish. Bobtail squid tend to have a rounder mantle than cuttlefish and have no cuttlebone . They have eight suckered arms and two tentacles and are generally quite small (typical male mantle length being between 1 and 8 cm (0.39 and 3.15 in)).
Sepietta oweniana (common bobtail squid or common bobtail) is a common marine mollusc from the order Sepiida, the cuttlefish. Common bobtails possess large, rounded pupils , eight arms each having biserial suckers and two arms with 32 tiny uniform-sized suckers in transverse rows to be used for securing their prey. [ 3 ]